Optimized production of aromatic dicarboxylic acids

Abstract

Disclosed is an optimized process and apparatus for more efficiently and economically producing aromatic discarboxylic acids. The process reduces costs associated with hydrogenation by forming a final composite product containing unhydrogenated acid particles.

1. An apparatus comprising:
 an oxidation reactor having a reactor outlet; 
 a solid/liquid separator having a separator inlet, a separated solids outlet, and a separated liquids outlet, wherein said separator inlet is coupled in communication with said reactor outlet; 
 a splitter having a splitter inlet, a first splitter outlet and a second splitter outlet, wherein said splitter inlet is coupled in communication with said separated solids; 
 a hydrogenation system having a hydrogenation system inlet and a hydrogenation system outlet, wherein said hydrogenation system inlet is coupled in communication with said first splitter outlet; and 
 a combining zone having a hydrogenated solids inlet, an unhydrogenated solids inlet, and a composite solids outlet, wherein said hydrogenated solids inlet is coupled in communication with said hydrogenation system outlet, wherein said unhydrogenated solids inlet is coupled in communication with said second splitter outlet. 
 
     
     
       2. The apparatus of  claim 1  further comprising a crystallization system having a crystallization system inlet and a crystallization system outlet, wherein said crystallization inlet is coupled in communication with said hydrogenation system outlet, wherein said crystallization system inlet is coupled in communication with said hydrogenation system outlet. 
     
     
       3. The apparatus of  claim 2  further comprising a second solid/liquid separator having a second separator inlet, a hydrogenated solids outlet, and hydrogenated liquids outlet, wherein said second separator inlet is coupled in communication with said crystallization system outlet, wherein said hydrogenated solids outlet is coupled in communication with said hydrogenated solids inlet. 
     
     
       4. The apparatus of  claim 3  further comprising one or more hydrogenated solids dryers having a dryer inlet and a dryer outlet, wherein said dryer inlet is coupled in communication with said crystallization system outlet, wherein said dryer outlet is coupled in communication with said hydrogenated solids inlet. 
     
     
       5. The apparatus of  claim 1  wherein said oxidation reactor is an agitated reactor. 
     
     
       6. The apparatus of  claim 5  wherein said oxidation reactor is a mechanically-agitated reactor. 
     
     
       7. The apparatus of  claim 5  wherein said oxidation reactor is a bubble column reactor. 
     
     
       8. The apparatus of  claim 1  wherein said solid/liquid separator is selected from the group consisting of a decanter centrifuge, a rotary disk centrifuge, a belt filter, and a rotary filter. 
     
     
       9. The apparatus of  claim 1  further comprising a catalyst recovery system having a recovery inlet and a recovery outlet, wherein said separated liquids outlet is coupled in communication with said recovery inlet. 
     
     
       10. The apparatus of  claim 9  wherein said catalyst recovery system has a waste outlet and a clean liquid outlet, wherein said oxidation reactor has a feed inlet, wherein said clean liquid outlet is coupled in communication with said feed inlet. 
     
     
       11. The apparatus of  claim 1  further comprising one or more dryers having a dryer inlet and a dryer outlet, wherein said dryer inlet is coupled in communication with said separated solids outlet, wherein said dryer outlet is coupled in communication with said splitter inlet. 
     
     
       12. The apparatus of  claim 1  wherein no hydrogenation treatment system is disposed between said second splitter outlet and said unhydrogenated solids inlet. 
     
     
       13. The apparatus of  claim 1  wherein said splitter is configured to receive solids in said splitter inlet and split said solids into a first portion exiting said first splitter outlet and a second portion exiting said second splitter outlet, wherein said splitter is configured to discharge from said second splitter outlet at least 1 weight percent of said solids received in said splitter inlet. 
     
     
       14. The apparatus of  claim 13  wherein said splitter is configured to discharge from said second splitter outlet in the range of about 3 to about 60 weight percent of said unhydrogenated solids received in said splitter inlet. 
     
     
       15. The apparatus of  claim 13  wherein said splitter is configured to discharge from said second splitter outlet in the range of 5 to 40 weight percent of said unhydrogenated solids received in said splitter inlet. 
     
     
       16. The apparatus of  claim 1  wherein said splitter is configured to receive solids in said splitter inlet and split said solids into a first portion exiting said first splitter outlet and a second portion exiting said second splitter outlet, wherein said splitter is configured such that the weight ratio of solids exiting said second splitter outlet to solids exiting said first splitter outlet is in the range of about 0.01:1 to about 4:1. 
     
     
       17. The apparatus of  claim 16  wherein said splitter is configured such that the weight ratio of solids exiting said second splitter outlet to solids exiting said first splitter outlet is in the range of about 0.05:1 to about 2:1. 
     
     
       18. The apparatus of  claim 16  wherein said splitter is configured such that the weight ratio of unhydrogenated solids exiting said second splitter outlet to unhydrogenated solids exiting said first splitter outlet is in the range of 0.1:1 to 1:1. 
     
     
       19. The apparatus of  claim 1  wherein said hydrogenation system comprises an initial dissolution vessel and a hydrogenation vessel. 
     
     
       20. The apparatus of  claim 1  wherein said combining zone is configured to receive solids in said unhydrogenated solids inlet and to receive solids in said hydrogenated solids inlet, wherein the weight ratio of solids received in said unhydrogenated solids inlet to solids received in said hydrogenated solids inlet is in the range of about 0.01:1 to about 4:1. 
     
     
       21. The apparatus of  claim 20  wherein the weight ratio of solids received in said unhydrogenated solids inlet to solids received in said hydrogenated solids inlet is in the range of about 0.05:1 to about 2:1. 
     
     
       22. The apparatus of  claim 20  wherein the weight ratio of solids received in said unhydrogenated solids inlet to solids received in said hydrogenated solids inlet is in the range of 0.1:1 to 1:1. 
     
     
       23. The apparatus of  claim 1  wherein said oxidation reactor has a feed inlet and an oxidant inlet that are separate from one another, wherein said feed inlet is configured for receipt of a liquid phase feed stream comprising an oxidizable compound, wherein said oxidant inlet is configured for receipt of a gas phase oxidant stream. 
     
     
       24. The apparatus of  claim 23  wherein said oxidation reactor is configured to continuously receive said oxidizable compound at a rate of at least 5,000 kilograms per hour. 
     
     
       25. The apparatus of  claim 23  wherein said oxidation reactor is configured to continuously receive said oxidizable compound at a rate of 10,000 to 80,000 kilograms per hour.